diff options
Diffstat (limited to 'usr/src/uts/common/fs/zfs/arc.c')
| -rw-r--r-- | usr/src/uts/common/fs/zfs/arc.c | 56 |
1 files changed, 55 insertions, 1 deletions
diff --git a/usr/src/uts/common/fs/zfs/arc.c b/usr/src/uts/common/fs/zfs/arc.c index e88213a491..cc5143e4df 100644 --- a/usr/src/uts/common/fs/zfs/arc.c +++ b/usr/src/uts/common/fs/zfs/arc.c @@ -20,7 +20,7 @@ */ /* * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved. - * Copyright (c) 2019, Joyent, Inc. + * Copyright 2020 Joyent, Inc. * Copyright (c) 2011, 2018 by Delphix. All rights reserved. * Copyright (c) 2014 by Saso Kiselkov. All rights reserved. * Copyright 2017 Nexenta Systems, Inc. All rights reserved. @@ -4399,6 +4399,7 @@ typedef enum free_memory_reason_t { FMR_PAGES_PP_MAXIMUM, FMR_HEAP_ARENA, FMR_ZIO_ARENA, + FMR_VIRT_MACHINE, /* 'VM' seems ambiguous in this context */ } free_memory_reason_t; int64_t last_free_memory; @@ -4414,6 +4415,48 @@ int64_t arc_pages_pp_reserve = 64; */ int64_t arc_swapfs_reserve = 64; +static volatile uint64_t arc_virt_machine_reserved; + +/* + * XXX: A possible concern is that we allow arc_virt_machine_reserved to + * get so large that we cause the arc to perform a lot of additional + * work to keep the arc extremely small. We may want to set limits to + * the size of arc_virt_machine_reserved and disallow reservations + * beyond that limit. + */ +int +arc_virt_machine_reserve(size_t pages) +{ + uint64_t newv; + + newv = atomic_add_64_nv(&arc_virt_machine_reserved, pages); + + /* + * Since arc_virt_machine_reserved effectively lowers arc_c_max + * as needed for vmm memory, if this request would put the arc + * under arc_c_min, we reject it. arc_c_min should be a value that + * ensures reasonable performance for non-VMM stuff, as well as keep + * us from dipping below lotsfree, which could trigger the pager + * (and send the system toa grinding halt while it pages). + * + * XXX: This is a bit hacky and might be better done w/ a mutex + * instead of atomic ops. + */ + if (newv + arc_c_min > arc_c_max) { + atomic_add_64(&arc_virt_machine_reserved, -(int64_t)pages); + return (ENOMEM); + } + + zthr_wakeup(arc_reap_zthr); + return (0); +} + +void +arc_virt_machine_release(size_t pages) +{ + atomic_add_64(&arc_virt_machine_reserved, -(int64_t)pages); +} + /* * Return the amount of memory that can be consumed before reclaim will be * needed. Positive if there is sufficient free memory, negative indicates @@ -4477,6 +4520,17 @@ arc_available_memory(void) r = FMR_PAGES_PP_MAXIMUM; } + /* + * Check that we have enough memory for any virtual machines that + * are running or starting. We add desfree to keep us out of + * particularly dire circumstances. + */ + n = PAGESIZE * (availrmem - arc_virt_machine_reserved - desfree); + if (n < lowest) { + lowest = n; + r = FMR_VIRT_MACHINE; + } + #if defined(__i386) /* * If we're on an i386 platform, it's possible that we'll exhaust the |